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\textbf{Use Case S2:  Detailed Description}\\\\
Use Case Name:  Monitor Humidity Data\\
Scenario:  N/A\\
Brief Description:  With the System running, the System monitors the
the humidity data by periodically requesting humidty data from the
1-wire temperature sensor.\\
Actors:  System\\
Related Use Cases:\\
\textbf{Use Case A1:}\emph{The Administrator shall set the
Measurement Reate for all active hardware sensors}\\
\textbf{Use Case S10: }\emph{The System Shall Save Humidity data}\\
\textbf{Use Case S11: }\emph{The System Shall Monitor and Save
Humidity Extreemes}\\
\textbf{Stakeholders: } Local and National Weather Bureaus, other
systems and users monitoring local weather data.\\
\textbf{Preconditions:  } The System is running, the Measurement
rate is set, the network is setup and working, the hygrometer 
hardware is connected to the network.\\
\textbf{Postconditions: } The Raw Humidity data is received from the
hygrometer hardware and converted to an actual Relative Humidity
value.  The Relative Humidity data is received from the hygrometer
hardware.\\\\
\textbf{Flow of Events}\\
\begin{tabular}{|l|l|}\hline
\textbf{System} & \textbf{One Wire Temperature Sensor}\\\hline
1.  Periodically request raw humidity data & \\
from the One Wire Humidity Sensor & 2.  Returns the raw humidity
data\\ & (the supply and output voltages)\\\hline
3.  Converts the raw humidity data & \\
(input and supply voltages) & \\into relative humidity & \\\hline
4.  Periodically request humidity data & \\
from the One Wire Humidity Sensor & 5.  Returns the relative
humidity data\\\hline
\end{tabular}\\\\
\textbf{Exception Conditions}\\
2a.  If the One Wire Humidity Sensor stops working (drops out), then
the System shall handle the error and report a default humidity
(-99.9\%).\\
2b.  If the One Wire Humidity Sensor returns an error, then the
System shall handle the error and report a default humidity
(-99.9\%).\\
2c.  If the One Wire Network breaks, then the System shall report an
error and display default humidity value (-99.9\%).\\
5a.  If the One Wire Humidity Sensor stops working (drops out), then
\textbf{the System shall follow what is written in Section
\underline{2a} in the \underline{Exception Conditions} Section}.\\
5b.  If the One Wire Humidity Sensor returns an error, then
\textbf{the System shall follow what is written in Section
\underline{2b} in the \underline{Exception Conditions} Section}.\\
5c.  If the One Wire Network breaks, then \textbf{the System shall
follow what is written in Section \underline{2c} in the 
\underline{Exception Conditions} Section}.
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